Operation Alberich (Unternehmen Alberich) was the codename of a German Army military operation in France during World War I. It was a planned withdrawal to new positions on the shorter, more easily defended Hindenburg Line (Siegfriedstellung), which took place between 9 February and 20 March 1917 and eliminated the two salients which had been formed in 1916, between Arras and Saint-Quentin and from Saint-Quentin to Noyon, during the Battle of the Somme. The British referred to it as the German Retreat to the Hindenburg Line but the operation was a strategic withdrawal rather than a retreat.